Hydraulic jack



March 15, 1949. J. J; MUELLER HYDRAULIC JACK Filed'May 5, 1944 PatentedMar. l5, 1949 HYDRAULIC JACK `oseph J. Mueller, St. Joseph, Mich.,assigner to Auto Specialties Manufacturing Company, St. Joseph, Mich., acorporation of Michigan Application May 5, 1944, Serial No. 534,210

(Cl. Sil-62) 1 Claim. 1

This invention relates to hydraulic jacks, and while the invention iscapable of broad adaptation to a jack of the general principles hereinillustrated, the invention is for purposes of illustration, but not byway of limitation, shown as applied to a jack of the construction setforth in my co-pendng application Serial No. 468,768, filed December l2,1942, now patent No. 2,412,414, issued December 10, 1946.

Therefore one of the objects of the present invention is to provide ajack which is an improvement on the jack disclosed in my beforementioned application, and wherein a valve seat is formed in the upperend of the central bore of the stationary ram, and a valve rod and valveare mounted in the underside of the top portion of the slidable raincylinder so that when the cylinder is raised to a predetermined heightthe valve will cut olf the pressure fluid to the underside of the ramcylinder, whereby to prevent inf jury to the jack if the hydraulicpumping action be continued beyond Such predetermined lifting range.

Yet another object of the invention resides in providing a jack havingan upstanding stationary ram and a relatively slidable ram sleeveenveloping the ram, the top surface of the ram sleeve being providedwith a threaded plug, the head of which is arranged so that pressureagainst the underside of the ram sleeve normally tends to seal the plugmore tightly, the plug being provided with a central threaded apertureto receive and carry a depending valve rod cooperating with a sleeveprovided with a cornplementary valve seat therein formed in the upperportion of the central bore of the stationary ram cylinder, whereby tocut off further uid presure against the underside of the ram sleeve at apredetermined point in its elevation.

These and other objects of the invention will fr be apparent from thefollowing specification, when taken in connection with the accompanyingdrawing, wherein:

Figure 1 is a perspective View of one form of the invention;

Figure 2 is a sectional view taken on the line 2 2 of Figure 1;

Figure 3 is a sectional View taken on the line 3 3 of Figure 2;

Figure 4 is an enlarged section taken through the oil reservoir, showingthe by-pass valve; and

Figure 5 is a section corresponding to Figure 2, but showing the cut-offvalve in its uppermost position with respect to the stationary ramcylinder.

Referring now to the drawings in detail, the particular jack with whichthe invention is illustrated embodies a base 2 which is providedcentrally with an upstanding wall 4 providing a central well. Thecircular inner faces of the upstanding wall 4 are threaded as at 5. Ontothis threaded portion screws a stationary ram 8 having a centrallongitudinally disposed liquid passageway It. An elongated hollow ramcylinder in the form of the sleeve l2, preferably formed of malleableiron, encloses the stationary ram 8. This shiftable rain cylinder l2 isprovided with an inwardly extending shoulder Hi at its top and the uppersurface of the ram is suitably knurled or fashioned as at l to grip theload to be lifted. The top of the ram cylinder is preferably providedwith a screw threaded opening into which is threaded the plug 20. Thisplug is provided with a head 22 or; its inner end and with a hexagonalrecess 24 in its outer or top end. By this arrangement the fluidpressure within the ram cylinder l2 tends to forceA the plug tightly toits seat to prevent leakage. The ram cylinder i2 at its bottom issuitably threaded as at 39 to receive a packing 32 which lies betweenthe bottom of the stationary ram S and the inner smooth surface of theram cylinder l2. At its outer bottom end the ram cylinder is providedwith a foot lift step 34 which forms a second load receiving surface.The bottom of the ram 8 is recessed as at 36 and joins the internalpassageway It formed centrally of the ram. It is particularly to beobserved that there is a minimum of space between the external smoothwall of the ram and the internal smooth wall of the ram cylinder I2,other than that space demanded in order to permit the ram cylinder l2 toelevate or depress relatively to the stationary ram 8. By means of thisconstruction it will be noted that any oil which leaks into this spacebetween the external vertical face of the ram S and the internalvertical face of the ram cylinder I2, on elevation of the ram cylinderwill be permitted to escape upwardly to the space between the top of thestationary ram and the underface of the ram cylinder i2 and will not beforced downwardly past the packing 32. In this manner escape or seepageof the oil to an external surface of the ram cylinder is precluded.

Cast integrally with the upstanding wall li of the base is an oilreservoir 33. This reservoir is preferably cylindrically shaped and isdisposed laterally of the central axis or passageway I 0 of theupstanding ram 8. The cylindrical reservoir extends substantially fromone side of the base to the other, as indicated in Figures l and 3, andthis cylinder is provided with a threaded opening at each end, such asi0 and 02, to receive threaded plugs Ml and 46 whereby to facilitate thecasting of the reservoir as well as to permit the filling of the samewith suitable liquid, preferably oil. 'The plugs All and I6 arecountersunk at their outer ends in a hexagonal manner to permit theremoval and insertion of the same.

A plunger pump cylinder is cast integrally with the oil reservoir. Asshown in Figures 2 and 3, the walls 48 are internally formed centrallyof the reservoir, extending vertically downwardly as indicated in theabove mentioned figures. At the top the pump cylinder casting isshouldered as at 50 to receive a threaded packing plug or ring 52 whichserves to hold suitable packing 5d in position to prevent leakageoutwardly around the pump piston. A pump piston 5t is adapted to bereciprocatingly mounted within this cylinder and to this end the pumppiston is provided at its outer end with a cross bore 5B in which a pini523 is disposed, and the pump piston having at its inneror'opposite enda threaded shank to which is attached a nut 5I which supports a collar50 being surrounded by leather pump washer d i, as shown in Figure 3.The opposite ends of the pin 60 lie in registering apertures 62 and 5dof ears and 68 of an actuator 'l0 pivoted as at 'I2 to the outer end ofthe links 'lli which are in turn pivoted by means of the pin l to theears E52 integrally cast on the top surface of the reservoir 3S. Theactuator 'i0 is provided with a socket St in which an operating handleEB may be inserted whereby upon reciprocation of the handie in avertical plane the `high pressure pump will be actuated in a manner wellknown in the hydraulic jack art to draw liquid from within the interiorof the reser" voir 38 through the cast passageway @l0 past the ballvalve 92. This ball valve, as shown, is normally held by means of aspring aten its seat 96. The liquid will be drawn inwardly by an upwardmovement of the piston 55 into high pressure cylinder chamber 35i andthen upon downward movement of the piston. 5S the ball 92 will bepressed against the seat and the liquid will thence be transferred pastthe larger balltgthence through the transversely extendM ing castopening E00, thence through channel I02-I04`into the recess 36 of theram 8, thence up the longitudinal passageway I0 of the ram to cause theupward projection of the ram cylinder I2. The ball valve 08 is normallypressed to its seat by means of the spring 99.

A diagonally disposed passageway Iii@ connects the passageway Id? in thebase of the jack with the reservoir and the upper portion of this crosspassage I06 is provided with a valve seat E03 which is normally closedby means of a valve formed on the inner end of a valve stern IIi whichby means of the threads iii engages cerresponding threads on a sleeve Ii4 cast integrally withfthe inner walls Il of the reservoir. Suitablepacking Ihi held in position by means of a threaded thimbie preventsleakage past this valvefstem I iii. Rotation of the outer end of thehandle I2? of this valve stem opens communica tion between the reservoirand the passagewa I0? .so as permit the passage of liquid directly fromthe stationary ram f8 back into the resern voir whereby to release thepressure in the space between the ram and ram cylinder to permit thedescent orfdownwardiinward movement of the ram cylinder I2 relative tothe ram 8 and the base. It will be noted that by this arrangement and byforming the passageway IGS directly Within the inner wall of the oilcylinder, leakage is precluded since the oil in escaping must passdirectly into the oil reservoir.

It will be noted that passage |02 is closed at its outer end by asuitable threaded plug |03, and it will be likewise noted that thepassage I00 is closed by another threaded 4plug I 2d, and in order togive access to this plug the bottom portion of the casting is hollowedout arcuately as at I26.

The front wall of the reservoir 33 is provided with spaced outstandingears IZB to which are pivoted the opposite ends of a handle |30 forlifting the jack at its base.

It will be noticed from Figure 3 that the passageway 00 within the oilreservoir is arranged so that the end di of this passageway terminatesrelatively close to the vertical end wall 93 of the oil reservoir nearll plug 4.: By thisarrangement the jack can be positioned forhorizontaloperation on one of its sides, whereby reservoir.;

plug Lil-i is downward, and still draw iiuid through port 9i from thelowermost portion of the reser.

Voir.

In accordance with the improvedfeatures of-v this invention, means isprovided inassociation with the ram and ram cylinder,` and preferablythe central oil conduit i0, for limiting thevertical lift ol the ramcylinder I2 with respect to the sta.l

tionary ram 8. In the construction illustrated,-

tion of the passageway so as to prevent liquid `being forced intothe-space-between the. upper surface of the ram 8 and the undersurfaceof.. In the presentfinstance` this is accomplished Yby providing theyplug.:

the ram cylinder I 2.

20 with a threaded hole 95 to receive, an

elongated valve rod 91 Ahaving, on* its.b0ttom,Y

This valve is adapt-.

end a tapered valve 99. ed to seat against a valveseat IBI formed in -athreaded sleeve 03 which screws into a threaded internal bore it atthe'top of the `oil passage I0 of 'the ram t.

is provided with an unthreaded portion vIIl'l having inwardly taperingwalls H39 whereby to guide the valve 00 as it moves ydownwardlyv whenthe sleeve-like ram cylinder I2' descends. Inl the operation of thisdevice, when the ram cylinder I2 i reaches the position shown in Figure5, thetasageway I0 is thus cut oli no further elevation. of

the ram cylinder is possible so thatany attempt f to continuethevelevation of thefram cylinder will l prove fruitless.

Obviously the invention-.is not limited to the specific details ofconstruction disclosedwhereinmlbut is capable of other modifications-andchanges Without departing from the spirit and-scope of the.

appended claim. I

Having thus described my invention', what'l claim as new and desire ltosecure byLetters Pats. ent is:

In an hydraulic jack, the" combination of fa.

base, a ram stationarily` projecting- :upwardly` therefrom and Ahaving a'central-vertical liqui passage, a sleeve-like ram cylinderadalvtedrtoditk rihe bottom of this passage. in which the threadedsleeve IQE lthreadedl-y-engages over the ram, said jack having a liquidreservoir associated with the base, pumping means associated with thebase including passages interconnecting the reservoir, the pumpingmeans, and the central passage of the ram for drawing liquid from thereservoir and forcing it under pressure to the central passage of theram, oy-pass means for relieving the oil in the ram and passing it backto the reservoir, the upper portion of said vertical passage in said rambeing provided with an enlargement the upper portion of which isthreaded, a hollow sleeve screwing into the threads of said enlargement,the bottom inner wall of said sleeve being formed with tapering Wallportions forming a valve seat, the enlargement below said sleeve beingtapered conically inwardly and downwardly, the top of said ram cylinderhaving a central threaded opening, a plug having an external threadscrewing into said opening and having a head larger than said openingand disposed internally of said cylinder to seal said opening under thepressure conditions to which the underside of said head is subjected.said plug head having a central bore and a rodlike element mounted inthe central opening of the plug head and extending downwardly throughthe passage through said sleeve and provided on its lower end with atapered valve to close upon the valve seat formed by said sleeve, saidtapered walls of said enlargement forming a guide to center said valveas it moves downwardly.

JOSEPH J. MUELLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

